changing administrative mode of a 2900xl port

For the life of me I can't figure out how to change the administrative mode of a catalyst 2900xl switch.

On a 2950 I can do it with these commands:

switchport mode dynamic <AUTO|DESIRABLE>

Basically I can't get the 2900 to establish a trunk with a 2950 or 3550's. I can get trunks working between the 2950's and 3550's.

I have all of the switches using dot1q encapsulation.

Does anyone know of any particular settings that need to be set on a 2924xl to get it to trunk with a 2950 or 3500.

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Comments

mikej412

Catalyst 2900XL and 3500XL switches do not support DTP (last bullet in the section).

Netwurk

liven wrote:

Does anyone know of any particular settings that need to be set on a 2924xl to get it to trunk with a 2950 or 3500.

A 2924 uses ISL by default so you need to change your encapsulation to dot1q

Hopefully you have the EN model, as I'm not sure if the non-enterprise 2900 switches can do dot1q

Use switchport mode trunk on both ends (there may be other combos that work, but that one definitely will)

The 3500 is older and may also default to ISL, so you may need to change that also.

The 2950 is newer, so it will either default to dot1q or not have ISL support at all.